Thanks for all the answers (and references) to my question about the
quality of filtering in the cochlea, both here and by email. The
general consensus seems to be that the quality of filtering is not very
high.
My next question is about the implications of this in cases where the
hair cells are defective at some frequencies but not others. It seems
like the person would still hear tones of those frequencies, but they
would sound like other frequencies, and would have a higher threshold.
But an audiogram does not ask what the tones sound like, just whether
they can be heard at all. Thus, some people who are actually 100% deaf
at some frequencies but have normal hearing at others, might have a
very misleading audiogram.